Locking device for incandescent lamps.



G. J. TIMM &: J. A. BARNHARDT. LOCKING DEVICE FOR INGANDESGENT LAMPS.

APPLIOATION FILED APR. 27, 1909.

959,818. Patented May 31,1910.

l-nventoufiv A rmrdf a 'Y rim. ed fa it sraras Parana caries.

CLARENCE J. TIMIVI AND JAMES A. BARNHARDT, OF DULUTH, MINNESOTA.

LOCKING DEVICE FOR INCANDESCENT LAMPS.

arms I s.

'11) all whom it may concern:

Be .it known that we, CLARENUE J. Turn and James A. BAKNIIARD'L,citizens of the United States, residin at Duluth, in the county of St.Louis and State of Minnesota, have invented certain new and usefulImprovements in Locking Devices for Incandescent Lamps, of which thefollowing is a specification.

This invention comprehends means for preventing the unauthorized andsurreptitious removal of incandescent lamp bulbs from their sockets, bythe provision of looking means which will be simple in construction anddurable, and which will ell'ectually prevent the lamp from being removedeX- cept by breaking the globe.

To this end the invention consists essentially in an incandescent lampwhich is provided at its base with a catch, designed, when the base isscrewed into the casing or key socket to spring into locking engagementwith a keeper formed in the socket, thereby preventing the detachment ofthe lamp from the socket without first breaking the globe of the lamp.And the invention also consists in certain arrangements and combinationsof the parts that we shall hereinafter 1 describe and claim.

For a full understanding of the invention and the merits thereof,reference is to be had to the following description and accompanyingdrawings, in which;

incandescent lamp embodying the improvements of our inventlon. Fig. 2 1sa hOIlzontal sectional View thereof, on an enlarged scale, being takenapproximately on the line 22 of Fig. 1. Fig. 3 is a perspective view ofthe base end of the lamp. Fig. 4 is a detail perspective view of thespring catch. Fig. 5 is an enlarged fragmentary section of the base ofthe lamp showing the groove formed therein to receive the spring catch.

Corresponding and like parts are referred to in the followingdescription, and indicated in all the views of the drawings by the samereference characters.

Referring to the drawings, the numeral 1 designates a key socket for anincandescent lamp, and 2 designates the lamp, each of these parts beingof any desired design and construction, except as hereinafter noted.

3 designates the base of the lamp 2 which is formed Withthe usual screwthreads by Specification of Letters Patent.

Application filed April 27, 1909.

@inner wall of the socket 1.

Patented May 31, 1910.

Serial No. 492,497.

which it may be screwed into the correspondingly threaded inner vall ofthe socket 1.

The base 3 of the lamp carries a spring catch 4 which is so arrangedthat it will be held in restrained or retracted position during theoperation of screwing the base into the socket, and which will, when thebase is fully screwed in and is moved rearwardly in any attempt todetach the lamp, spring into a keeper or opening 5, formed in the Thespring catch 4 may be formed in any desired way or he of any desireddesign and the keeper 5 may be formed in any manner, as we do not wishour invention to be limited in these respects, for various changes inthe construction, relative arrangement and proportion or design of theparts may be made, without departing from the scope of the invention asdescribed in the appended claims.

In the present embodiment of the invention, the spring catch 4 is formedof a single piece of spring wire, and it embodies a shank (3, insertedin a longitudinal groove 7 that is formed in the base 3. The catch 4 isformed at one end of the shank 6 with an angularly disposed extremity 8formed into a hook 9 with an outwardly projecting bill as shown, and inthe present instance the keeper 5 is formed by cutting or otherwisemaking an opening in the metal inner portion of the v i socket, wherethe threads are formed for en- I lgure 1 1s a sectional side elevationof an i gagement with the threaded base 3. The catch is provided at theother end of the shank G with a coiled portion of loop 10, whichpartially or completely encircles the lamp at the juncture of the globewith the base, said loop serving as a retaining means for detachablyholding the catch in position on the lamp before the same is connectedto the socket.

From the foregoing description in connection with the accompanyingdrawing, it is obvious that upon the screwing of the base 3 into thesocket 1, the hook 9 of the catch will finally register with the keeper5 and spring into locking engagement therewith, should any attempt bemade to subsequently unscrew the lamp from its socket.

As the spring catch 4 is preferably only detachably connected tothelamp, by having its shank 6 seated in the groove 7, for example, it ismanifest that a lamp base formed for our invention is not limited to usewith the locking device such as We have described, but is applicable forany ordinary lamp socket of the type herein disclosed, the formation ofthe groove 6 in nowise detracting from the general efiiciency of thedevice.

Having thus described the invention, What is claimed as new, is:

1. The combination with a lamp socket of the type described, formed inits inner Wall with a keeper, and a lam adapted to work into saidsocket, of a spring catch having a loop atone end and adapted toencircle the base of the lamp and a hook at its inner end adapted toengage said keeper.

2. The combination with a lamp socket of the type described and formedin its inner wall with a keeper, and a lamp adapted to be worked intosaid keeper by a rotary movement thereof, a catch having an intermediateportion extending longitudinally of the base of the lamp, and a hook atone end with an outwardly turned bill adapted to engage the keeper.

3. The combination with a lamp socket of the type described, formed inits inner wall with a keeper, of a lamp provided with a base formed witha longitudinal groove, and a spring catch having a shank seated 1n saldgroove and a hOOK designed to engage said keeper.

4. The combination with a lamp socket of the type described, formed inits inner wall Wit-l1 a keeper, of a lamp provided with a base formedwith a longitudinal groove and a spring catch having a shank seated insaid groove, a hook at one end of said shank, designed to engage saidkeeper, and a loop at the other end of said shank encircling the lamp.

5. The combination with a lamp socket of the type described, formed inits inner wall with a keeper, and a lamp provided with a base. adaptedto work into the socket by a rotary movement, of a catch having anintermediate portion extending longitudimilly of the base, a loop at oneend adapted to encircle the base, and a hook at the other end with anoutturned bill adapted to engage the keeper upon a reverse movement ofthe lamp and socket.

In testimony whereof we allix our signatures in presence of twowitnesses.

, CLARENCE J. TIMM.

JAMES A. BARNHARDT. \Vitnesses:

E. G. KREIDLER, J. C. RIESLAND.

